Effect of planting dates and different rates of seed on forage yield of berseem clover in double cropping system in Shahrekord region

Double cropping is one method for improve production of crops. In order to study the effects of planting date and seeding rate on berseem clover forage yield in double cropping system, an experiment was carried out in split plot based on Randomized Complete Blocks Design (RCBD) with 3 replications in Shahrekord agriculture research station in 2006-2007. Main and sub plots consisted three planting dates (6, 16 and 26 July) and three seeding rates (20, 25 and 30 kg ha-1) respectively. Berseem clover were planted in no tillage condition after harvesting canola. Two-year results showed that the most fresh, dry forage yield and plant height were obtained from 6 July with 19.26 and 4.78 ton ha-1 and 43.6 cm respectively that these traits were 1.4, 12.5 and 12.7 higher than second planting and 31.3, 54.8 and 69.7 percentage more than 26 July. Dry forage yield of 16 July was significantly increased (37.6 percentage) in compared with 26 July. No significant difference were in the among seeding rates for dry forage yield, although the most was obtained from seed rate of 30 kg ha-1, with 1.8 and 11.7 percentage higher in compared with 25 and 20 kg ha-1 respectively. Planting date had no significant effect on stem number per m2, but in the among seeding rates, the greatest was recorded with 405 of 30 kg ha-1. According to the results, the highest dry forage yield of berseem clover were harvested in 6 and 16 July with seeding rates of 25-30 kg ha-1 in double cropping system in Shahrekord region. So berseem clover can be used for forage production in the canola- wheat rotation.